To remove the paint, dirt or other surface coating from a substrate such as a surface to be painted or cleaned, a blasting system is both desirable and necessary. There are a variety of blasting processes for these purposes, including but not limited to, water blasting, dry abrasive blasting, and wet abrasive blasting. In certain applications, abrasive blasting systems are able to efficiently clean or remove a coating without damaging the underlying metal or other substrate. Although in other applications, a certain degree of surface roughening may be desired.
The use of dry abrasive blasting with particles such as those used in conventional sand blasting may result in surface roughness and other damage to the substrate. Typical blast particles are hard and abrasive in order to increase the efficiency of the blasting operation but may therefore result in damage to the substrate. Soft recyclable blast particles are sometimes substituted to avoid surface damage. These recyclable blast particles include, but are not limited to, agricultural products such as crushed walnut shells, crushed pistachio shells, and rice hulls. Plastic particles are sometimes used to reduce substrate surface damage but may also result in a reduction in efficiency of the blasting operation.
Wet abrasive systems have been used to also control surface damage. Wet abrasive systems combine the benefits of these blasting systems and dry abrasive blasting systems. In wet abrasive blasting, the fluid may encapsulate the abrasive media to simultaneously add mass to the abrasive and buffer the impact of the abrasive against the substrate to reduce potential surface damage but still effectively strip or clean the surface while also reducing the dust produced compared to a dry abrasive blasting system. However, wet abrasive systems require efficient mixing of slurry and a gas stream, to produce a consistent stream of a three-phase mixture of fluid, solid abrasive, and gas stream. If the mixing of slurry and pressurized gas is not well controlled, the blasting process is less efficient and the benefits of a wet abrasive system are not fully realized.
There is a need for a wet abrasive system that is easier to control in order that the benefits of a wet abrasive system are more fully realized.